1. Field of Invention
This invention is concerned with methods of controlling and combatting coccidiosis and improving rate of weight gain in ruminant animals, having been exposed to or infected with coccidia parasites, by oral administration of certain salinomycins, namely salinomycin and its 4-methyl derivative and their acceptable salts and C.sub.2 -C.sub.6 esters and salts thereof.
Uncontrolled development of the coccidia parasite in ruminant animals can debilitate the animal and aggravate other diseases present. Infection with coccidia in one animal can readily be spread throughout the entire group such as sheep and cattle in the feed lot through excretion of coccidia oocysts and subsequent ingestion by uninfected ruminants. The salinomycins interfere in the life cycle of coccidia in ruminants, reducing oocyst production and the spread of coccidiosis.
2. Description of the Prior Art
Use of salinomycin as an anticoccidial agent in chickens is disclosed in U.S. Pat. No. 3,857,948 and use of salinomycin in a method of increasing feed-utilization efficiency in a ruminant animal by increasing the proportion of propionate in the rumen has been disclosed in U.S. Pat. No. 4,085,224. Use of 4-methylsalinomycin to increase the proportion of propionate has also been disclosed in U.S. Pat. No. 4,009,262. The present invention is based on the finding that the salinomycins pass from the rumen into the gut and interfere in the life cycle of the coccidia parasite.
Medication such as decoquinate which is 6-decyloxy-7-ethoxy-4-hydroxy-3-quinoline carboxylic acid ethyl ester and amprolium have been used in prevention of bovine coccidiosis as described in the March, 1977 issue of the publication Animal Nutrition and Health, p. 6.